Configuring joins

You can query data from two tables by using joins. The join associates the rows from one table with rows from another table based on a specified condition, typically of matching column values.

About this task

Every object that is added to the canvas has two join ports. You can use the same join port to create multiple joins.

To create a join between any two objects, hold the left mouse button on the join port, drag the connection line over a different object on the canvas and then release the left mouse button.
To create a self-join between an object and itself, adding the object to the canvas twice and then create a join between those two instances of the object.

After you create a join, the Configure join page displays to configure the join condition.

Procedure

In the Configure join page, click Join type menu, and select the kind of joins for the database objects.
The following join types are supported:
- Inner join
- Left outer join
- Right outer join
- Full outer join
For example, if you selected the Left outer join or Right outer join, then the left object of the join coincides with the table you dragged from, and the right object coincides with the object you dragged to.
To join two objects on a single column, click the menu of each object and select a column for the join key.
To join the two objects on multiple columns, click Add join key to add more join keys.
Each column menu displays the data type, column name, whether the column is nullable, and whether it is a primary or a foreign key.
After you configure the join condition, click Save to save the join and return to the canvas.
To cancel the changes, click Cancel.
To edit or modify the join, on the canvas, click the key count on the join line that connects the two objects, or right-click the join line and select the Edit menu option.
To delete a join, click the x icon on the join line that connects the two objects, or right-click the join line and select the Delete menu option.